These events ALL happened a long time ago in a galaxy far, far away.
Even the nearest galaxies are tens of thousands of light years away. Although we only started receiving these Historical Documents in the 1970s, all of the beings in them are long dead. All of the aliens in the movies (like Han Solo) are played by human actors in theme parks here on Earth. Have your kids not figured it out? They know it's not the real Darth Vader but an enthusiastic and talented cosplayer. That's OK!
I suspect the Historical Documents have arrived out of order due to their hyperdrives allowing them to broadcast "later" events from locations within their galaxy that are dozens of lightyears nearer to us.
It is possible that the Skywalkers are not "aliens" in that humans arrived here by hyperdrive tens of thousands of years ago and it is only now that the broadcast has caught up with their descendants. Otherwise, it's one helluvan example of convergent evolution.
Did you know C-3PO's full name was Cylon-3 Prototype One? Maybe everyone shouldn't have mocked him so mercilessly...